[pitivi/1.0] previewers: Handle thumbnail not needed anymore

[Thibault Saunier <tsaunier src gnome org>]

commit f0b499a275fb5b4309af45b8c80fcea257a61569
Author: Alexandru Băluț <alexandru balut gmail com>
Date:   Tue May 29 21:45:41 2018 +0200

    previewers: Handle thumbnail not needed anymore
    
    By the time a thumbnail is done, it's possible we don't need it anymore.

 pitivi/timeline/previewers.py | 9 +++++++--
 tests/test_previewers.py      | 2 +-
 2 files changed, 8 insertions(+), 3 deletions(-)
---
diff --git a/pitivi/timeline/previewers.py b/pitivi/timeline/previewers.py
index 6d621034..9a947b10 100644
--- a/pitivi/timeline/previewers.py
+++ b/pitivi/timeline/previewers.py
@@ -633,7 +633,12 @@ class VideoPreviewer(Previewer, Zoomable, Loggable):
         position = self.position
         self.position = -1
 
-        thumb = self.thumbs[position]
+        try:
+            thumb = self.thumbs[position]
+        except KeyError:
+            # Can happen because we don't stop the pipeline before
+            # updating the thumbnails in _update_thumbnails.
+            return
         thumb.set_from_pixbuf(pixbuf)
         self.thumb_cache[position] = pixbuf
         self.queue_draw()
@@ -829,7 +834,7 @@ class ThumbnailCache(Loggable):
         Returns:
             List[int]: The width and height of the images in the cache.
         """
-        if self._image_size[0] is None:
+        if self._image_size[0] is 0:
             self._cur.execute("SELECT * FROM Thumbs LIMIT 1")
             row = self._cur.fetchone()
             if row:
diff --git a/tests/test_previewers.py b/tests/test_previewers.py
index ff705112..0d3c9912 100644
--- a/tests/test_previewers.py
+++ b/tests/test_previewers.py
@@ -148,7 +148,7 @@ class TestThumbnailCache(BaseTestMediaLibrary):
                 xdg_cache_home.return_value = tmpdirname
                 sample_uri = common.get_sample_uri("1sec_simpsons_trailer.mp4")
                 thumb_cache = ThumbnailCache(sample_uri)
-                self.assertEqual(thumb_cache.image_size, (None, None))
+                self.assertEqual(thumb_cache.image_size, (0, 0))
 
                 pixbuf = GdkPixbuf.Pixbuf.new(GdkPixbuf.Colorspace.RGB,
                                               False, 8, 20, 10)